Prior to 1912 there was no end zone and the goal line and end line were the same. With the introduction of the forward pass, the end zone was devised as a way for a receiver to catch a ball inbounds. Goal posts remained on the goal line until 1927 when they were moved to the back of the endzone. While they remained there in the college game the NFL in 1933 moved them back to the goal line until 1974 when they were once again moved to the end line.
Thus Super Bowls 1-8 plus any AFL seasons would have goalpost located at the front of the endzone and @fgqb#19nyj was kind enough to put together a tutorial on how to easily add this to your custom rom.
tiredtonsofclay reacted to Knobbe for a article, Moving the Goal Posts: A Hack for Classic NFL/AFL Roms